Problem: Simplify the following expression: $r = \dfrac{1}{6p} + \dfrac{1}{8p}$
Answer: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $6p$ and $8p$ $\lcm(6p, 8p) = 24p$ $ r = \dfrac{4}{4} \cdot \dfrac{1}{6p} + \dfrac{3}{3} \cdot \dfrac{1}{8p} $ $r = \dfrac{4}{24p} + \dfrac{3}{24p}$ $r = \dfrac{4 +3}{24p}$ $r = \dfrac{7}{24p}$